Cutter for thin wall tubing



March 3, 1959 c. c. BAUMAN CUTTER FOR THIN WALL TUBING File d Aug. 25', 1957 INVENTOR, QARL. C. BAUMAN ATTORNEYS CUTTER FOR THIN WALL TUBING Carl C. Bauman, Springfield, 111. Application August 23, 1957, Serial No. 679,989

1 Claim. (Cl. 30-101) This invention relates to pipe cutting devices.

During the pouring of concrete floors or slabs, electrical conduits, tubing, and pipes are stubbed or cut off above the surface of the slab, at a distance of perhaps 6 to 18 inches from the slab. During the construction of the building, said tubing is often broken or bent, making it necessary to chisel a large hole in the concrete about the tubing in order to cut the tubing and extend the stub to the proper height.

This operation, up to the present time, has been accomplished only with considerably difficulty, due to the great difiiculty of inserting a tubing cutting device, at a location below the level of the concrete slab.

The main object of the present invention is to provide a device which is particularly adapted for performing the tubing cutting operations, in the environment described above.

More particularly, the invention has among important objects thereof, the following:

To provide a manually operable device of simple, rugged construction, capableof manufacture at low cost;

To permit the tubing to be cut ofi cleanly, and with minimum difliculty;

To permit swift adjustment of the cutting tool to tubes of different diameters; and

To provide for minimum disturbance of adjacent portions of the concrete.

Other objects will appear from the following description, the claims appended thereto, and from the annexed drawing, in which like reference characters designate like parts throughout the several views, and wherein:

Figure 1 is a top plan view of a tubing cutter according to the invention;

Figure 2 is a longitudinal section on line 2--2 of Figure 1, the dotted lines showing a concrete slab and tube with the invention operatively applied thereto;

Figure 3 is a transverse section on line 3-3 of Figure 2; and

Figure 4 is a longitudinal section of line 4-4 of Figure 1.

Referring to the drawing in detail, designated generally at is the tube cutter constituting the present invention. This includes a circular, thick base plate 12, having wide, radially outwardly opening peripheral recesses 14 angularly spaced 120 apart about the circumference of the base plate. Extending across each recess 14 is apivot pin 16, the opposite ends of which are engaged in openings provided in the opposite side walls of the recess.

Pivotally supported from the base plate 12 by means of the pin 16 are elongated, straight arms 18. These extend downwardly from the base plate, swinging about axes that are disposed in the plane of the base plate and that extend chordally of the base plate adjacent the periphery thereof. Thus, the several arms swing in planes that perpendicularly intersect the planes of the base plate and that are extended radially of the base plate.

Adjacent the distal, lower end of the arms 18, the inner United States Patent 0,"

2,875,517 Patented Mar. 3, 1959 surfaces of the arms are formed with deep, laterally inwardly opening recesses 20, and extending across the recesses 20, in parallel relation to the longitudinal medians of the arms, are screws 22 providing pivot pins for cutters 24, 24, and a roller 28. The cutters 24 have hubs 26, and the roller is also provided with a hub, to prevent binding of the cutters and rollers against the walls of the recesses 20. Referring to Figure 3, it will be seen that there are two cutters, and one roller, in a typical working embodiment of the invention.

The cutters thus rotate in planes perpendicular to the length of the respective arms, this being true also of the roller, with the peripheries of the cutters and of the roller projecting inwardly beyond the inner surface of the arm, was to engage the outer surface of a tube T that is embedded in a concrete slab S.

Welded or otherwise fixedly secured to base plate 12, centrally of the base plate, is a stub-like torsion bar or shank 30, the length of which is perpendicular to the plane of the base plae. Adjacent the outer end of the shank 30,,there is a cross bar 32 providing a handle. The cross bar may be removably engaged in a diametrically extending bore of the shank. Alternatively, it may be integrally or otherwise fixedly connected to the shank.

Referring to Figure 1, formed in the periphery of base plate 12 are depressions or recesses 33, adjacent the respective recesses 14, the depressions 33 being for the purposes of permitting insertion or removal of the pins 16.

Means is provided for shifting the distal ends of the arms 18 radially inwardly toward the tube T. To this end, formed in the outer surfaces of arms 18, intermediate the ends of the arms, are rectangular notches 34, receiving a clamping band 36 formed of spring metal material,

said clamping band being of endless formation, and

screw 40 extends through the nut 38 and opening 39, I

bearing against the inner surface of one of the notches 34 as shown in Figure 4.

By reason of this arrangement, it will be apparent that on threading of the screw inwardly of nut 38, the several arms will be forced, at their distal ends, radially inwardly by pressure of the band and of the screw thereagainst, thus causing the roller 28 and cutters 24 to bear against the outer surface of the tube T. The device is then turned bodily, so that the cutters follow a circumferentially' extending path, whereby to cut through the material of the tube. As the cut becomes deeper, the screw can be tightened progressively, as will be understood.

In use of the tool, the conductor pipe that has been broken or bent is first straightened so as to extend at to the floor surface of the slab S. Then, the pipe may be cut off with a hack saw at or immediately above the floor surface. Then a masonry drill is used, to drill a hole in the concrete about the tubing, said hole being designated at H in Figure 2. The tool is then placed in position as shown in Figure 2, with the cutters below the floor surface, and operated in the manner previously described. When the tubing has been cut off, proper connections can be made to bring the tubing to the proper height.

It is believed apparent that the invention is not nec-. essarily confined to the specific use or uses thereof described above, since it may be utilized for any purpose to which it may be suited. Nor is the invention to be necessarily limited to the specific construction illustrated and described, since such construction is only intended to be illustrative of the principles, it being considered that the invention comprehends any minor change in construction that may be permitted within the scope of the appended claim.

' wear is claimed is:

A tube cutter comprising: a base 'plate;*a torsion-bar invplanes radiating fromth'e center of thebase plate,

for swinging of the arms toward'and away'from"the center of said space; cutter means carried by the arms and spaced longitudinally of the arms from the base plate; handle means on the torsion bar 'for'rotating the same; and means extending about the arms for swinging the same radially inwardly of a tube about which: the arms are spaced for engagingthe cutter means against the Iwall vof the tube said last named means being 'disposed Wholly exteriorly of the center space, said center space beingfree of obstructions over the full'distance from the cutter means to the'base plate, comprising'a band "circumposed about the several .arms and a screw havinga threaded connection to the band and projecting radially inwardly of the band into engagement with one of the arms, whereby said screw and band will shift'the arms radially inwardly of the tube about which the arms are spaced, responsive to threading of the'screw ina direction radially inwardly of the band, the several arms having intermediate their ends outwardly opening notches receiving the band, said'notches having top and bottom walls lying in planes approximately perpendicular to the length of the arms, the band having top and bottom edges lying in planes also approximately perpendicular to the length of the arms, said top and bottom edges being slidably engaged by the top and bottom Walls, respectively, of the notches, said band being of annular, endless form, the band being of a thickness substantially less than the depth of the notches, and being slidable within a selected, screw-receiving notch responsive to threading of the screw in a selected direction in said selected notch} References Cited in the file of this patent UNITED STATES PATENTS 1,085,967 Brown Feb. 3, 1914 1,107,511 Gallagher et a1 Aug. 18,1914 1 1,138,395 Nelson May 4, 1915 2,526,955 Kugler Oct: 24, 1950 FOREIGN. PATENTS 864,541 Germany Jan. 26, 1953 

